What is the best lens/technique for shooting products

I've been shooting new products that come off our assembly line for years for promotional purposes both in web and print. I've been using a high end point and shoot and cleaning the images up as best as I can using Photoshop. The results are acceptable, but not even close to professional.

I want to take the photo quality to the next level using my Canon EOS 400D (50mm lens and a generic 18-130), but I can never get enough of the product in focus due to the high depth of field in the Canon, even with the aperture set to 22.

My question is can I get the all in focus / high resolution results with this camera and lens combo or will I need to invest in another lens to get the job done? and if I do have what it takes, what is the best technique for this type of photography?